Thiophthenes



United States Patent 3,189,618 THIOPHTHENES Wallace R. Brasen, Lynmield, Wilmington, Del, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Aug. 31, 1961, Ser. No. 135,116 12 Claims. (Cl. 260- 329) This invention relates to a new class of heterocyclic organic compounds containing fused thiophene rings, and to a method for preparing them.

Polycyclic compounds with fused-ring structures are used widely as dyes or pigments, or as intermediates in the synthesis of dyes and pigments. Such compounds containing one or more amino groups as substituents are especially useful, because of the many synthetic reactions into which the amino groups can enter. These reactions include condensation with carbonyl compounds, diazotization followed by replacement of the diazonium group, dehydrogenation to give azo linkages, and cyclization to give additional fused heterocyclic rings containing nitrogen atoms. Only a few monoamino derivatives of compounds containing two fused thiophene rings have been made, and the methods involve many steps and give low overall yields. No diamino derivatives of such polycyclic compounds are known.

It has now been found that certain substituted diaminothieno(3,2-b)thiophenes and diaminothiophthenes can be easily prepared in good yield by the self-condensation of readily available dicyanoethylene bis(substituted-methyl sulfides) in the presence of a base. Specifically, a 3,6- diamino-2,5-disubstituted-thieno(3,2-b)thiophene (I) is prepared by bringing a 1,2-dicyanoethylene bis(substitutedmethyl sulfide) into contact with a base:

(1) NC SCHzR S mN R R] S NH,

0 base 2 N CN H N -Nn,

a] H-R' s s 0 base In the process and products of the invention, R and R are electron withdrawing groups, including CN, NO perfluoroalkyl of up to 12 carbons,

NC/ scrim Roms sornR' o 0 0 --&H, -i :-R", -SO3R, i-o-R" 0 o o i- NH,, i NH R" and i-N wherein R is hydrocarbyl of up to 12 carbons, and Q and Q may be the same ordifierent and are hydrocarbyl,

the total number of carbons in Q plus Q being up to 12. Preferably, R and R are 3,139,618 Patented June 15, 1965 "ice or -CN, wherein R" is as defined above, particularly those in which R plus R have a total of up to 14 carbons.

Any base having a pK value of less than about 7.5 may be used in the process of the invention. The symbol pK designates the negative logarithm of the basic dissociation constant (K Thus, the stronger the base, the lower the value of pK (For a brief discussion of pK see Organic Chemistry, Fieser and Fieser, 3rd ed..(1956), p. 226.) Naturally the stronger bases drive the reaction to completion more rapidly, and therefore, bases having a pK value of less than about 5.5 are preferred, particularly the alkali-metal hydroxides, alkaline earth metal hydroxides and quaternary ammonium hydroxides which have a p31,, of about -l.7. Examples of bases having a pK less than about 5.5 are ammonia; primary, secondary and tertiary alkyland cycloalkylamines (e.g., n-butylamine, cyclohexylamine, dimethylamine, and triethylamine); secondary or tertiary heterocyclic amines (e.g., piperidine and N-methylpyrrolidine); quaternary ammoniurn hydrom'des (e.g., benzyltrimethylammonium hydroxide); and alkali metal and alkaline earth metal hydroxides (cg, sodium hydroxide or barium hydroxide). Bases having a pro, between about 5.5 and 7.5 include, e.g., triethanolamine (6.23), diethyl-p-toluidine (6.91) and diethylaniline (7.44).

The molar ratio of base to dicyano compound should be at least 0.01:1.0 and preferably is in the range of 0.5:1.0 to 4021.0. Amounts in excess of 4021.0 can be used but ofier no advantage.

Although it is not essential, the process is preferably carried out in an inert solvent for the compound to be cyclized and the base. Examples of such mutual solvents are alcohols, such as ethyl alcohol; glycols, such as 1,2- dihydroxypropane; partly or completely etherified glycols, such as 1-methoxy-2-hydroxyethane and 1,2-dimethoxy' ethane; other acyclic or cylic ethers, such as ethyl ether, tetrahydrofuran, and 1,4-dioxane; sulfoxy compounds, such as dirnethyl sulfoxide and tetramethylene sulfone; and nitriles such as acetonitriie and propionitrile.

The temperature and pressure at which the process is carried out are not critical, and therefore, ordinary temperature and ambient pressure are conveniently employed. Higher or lower temperatures and pressures can be used but in general provide no advantage.

The time required varies considerably depending upon the reactant, the solvent, and the base. The reaction may be complete Within a minute or two or may require as long as 2-4 hours. The products of the invention are less soluble in the reaction medium than the starting materials, and therefore usually precipitate as they are formed. When precipitation ceases, the reaction is complete. The products are crystalline solids and can be isolated by conventional techniques, e.-g., by filtration or centrifugation followed by recrystallization.

The dicyanoethylene bis(substituted-methyl sulfides) used as starting materials are readily prepared by the reaction of a dicyanoethylene dimercaptide with the appropriate organic halide or halides. For examples, see Bahr and Schleitzer, Ben, 90, 442 (1957); Van Schoor et 211., German 1,060,655 (Merck, A.G., 1959); and Edwards and Kendall, US. 2,533,233. Sodium 1,2-dicyanoethylene dimercaptide is made by the method of Bahr and Schleitzer (above). The preparation, but not the isolation, of the isomeric sodium 1,1-dicyanoethylene dimercaptide is described in US. 2,533,233. The same sodium salt is The products of this more conveniently prepared, and isolated, by the proce-' Thus, 1,2-dicyanoethylene bis(substituted -methyl sul- V fides) and in which R and R are the same are prepared by reacting two equivalents of organic halide (RCH X, wherein X is halogen) with 1,2 -dicyanethylene dimercaptide. Sulfides in which R and Rare difierent can be prepared by reacting a 1,2-dicyanoethylene dimercaptide with one equivalent of an organic halide (RCHgX, where X is halogen) and reacting the 1,2-dicyanoet hylene mono (substituted-methyl) sulfide mercaptide thus obtained with one equivalent of a second organic halide (RCI-I X, where Xis halogen). It is not necessary to isolate the intermediate mono(substituted-methyl) sulfide mercaptide. This procedure is described for an alkyl halide and an acyl halide in Krespan, US; Patent 3,140,295, issued July 7, 1964. For example, the first 1,2-dicyanoethylene bis (substituted-methyl sulfide) in the firstcolurnn of Table I, infra, can be made by reacting sodium 1,2 dicyanoethylene dimercaptide with one equivalent of chloroacetamide, ClCI-I CONH and reacting the product with one equivalent or" phenyl chloroacetate, c1cH C00c H The order in which the two organic halides are used is immaterial;

'in the example just described, the preparation could be conducted just as well by reacting the 1,2-dicyanoethylene dimercaptide first with phenyl 'chloroacetate and then with V chloroacetamide.

Ifdesired, the dicyanoethylene bis(substituted-methyl sulfide) can be prepared and used directly without being isolated from the reaction mixture. as illustrated by Examples 2-5, infra.

The products of the invention also include the compounds of Formulas I and II, supra, in which one or both of certain R and R groups have been hydrolyzed to the carboxyl group'(-COOH'). Thus, all products of the invention are of one of the formulas:

(III) e and H N NHg A A wherein A and A, which may be the same or difierent,

' are R, R or the carboxyl group, R and R being as heretofore defined. Preferably, A and A are selected from the and'S0ns, pp. 411-417.] As will be apparent tothose skilled in the chemical arts, when a'compoundbears two.

(or more) hydrolyz'able groups, e.g., when both R and R a in Formulas I or II are hydrolyzable groups, either one or both of such groups can be converted to -COOH by proper choice of process conditions. Of course, when only one such group is present, it may be readily con verted to the carboxyl group without altering the otherR substituent, i.e.', NO CHO, COR", SO or perfluoroalkyl. V V

invention are well-defined crystalline solids that are stable to air and water. They are soluble solvents such as dirnethylformamide and acetonrtrlle and insoluble in water, ethyl alcohol, and benzene.

They can be recrystallized fromliqu'ids such as dimethylformarnide. They can be reacted with aromatic aldehydes' to give colored materials'useful, as dyestuffs.

The following examples, in which'all" parts are by 'weight'and which were all conducted at atmospheric pres sure, illustrate the process and products of this invene tion. 7

, E MP 1 V 3,6-dizmzzino2,5dibenzoylthien0(3,2-b)thiophene A solution of 3.8 p arts o f 1,2-dicyanoethylene bis-' (benboylmethyl sulfide) and 19.5 parts of acetonitrile was treated with one part of triethylamine (pK 3. 25). The resulting solution, after standing overnight, had deposited EXAMPLE 2 3,4didmin0-2,5-dibenzoylthiophtliene N I-I NH V 11 J A solution of 20 parts of phenacyl bromide in 40 parts of ethanol was added to a solution of9.3 parts of the disodium salt of dicyano-l,l-ethylenedithiol in 40 parts of ethanol. The resulting solution was boiled underreflux for one-half hour, during which time sodium bromide precipitated. The addition of 11 parts of triethylamine to the hot solution resulted in'precipitation of bright-yellow," crystalline 3,4-diamino-2,5-dibenzoylthiophthene. Recrystallization of this solid from dirnethylformamide yielded 8 parts (42%) of yellow plates, M.P. 300 C. 1 j

Analysis.Cal0d. for C20H14N2S2O2 C, H, N, 7.40; S, 16.95. Found: C, 63.64; H, 3.83; N, 8.03; S, 16.86.

The infrared spectrum of this product was compatible with the above structure.

. EXAMPLE 3 3,4.-diaminc-2,S-dibenzoylthiop hthene of carbon disulfide in 40 parts of ethanol was combined with 20.2. parts of triethylamine with cooling. The re sulting viscous yellow solution of the bistriethylaminoniumlsalt of dicyano-l,l-ethylenedithiol was added to a' 1 solution of 40 parts of phenacyl bromide in 79 parts of ethanol. The solution was boiled under. reflux for one- V A solution of 6.6 parts of malononitrile and 7.6 partswith 32 parts of triethylamine. The yellow precipitate which formed was recrystallized from dimethylformamide to yield 26.5 parts (70%) of 3,4-diamino-2,5-dibenzoylthiophthene.

Although triethylamine was used both in the preparation of the dicyano compound and the thiophene product, it is not essential that the same base be used in each instance when the dicyano compound is reacted in situ, i.e.,

without previous isolation from its reaction mixture.

EXAMPLE 4 3,4-a'z'amino-2,5-dicyan0thi0phthene Example 3 was repeated, except that 33.4 parts of ethyl bromoacetate was used in place of parts of phenacyl bromide, to give 1,1-dicyanoethy1ene bis(carbethoxymethyl sulfide) as an intermediate. The yield of 3,4-diamino- 2,S-dicarbet-hoxythiophthene was 56.5 parts (90% of theory), M.P. 202 C.

Analysis.Calcd. fOl' C12H14O4N2S2Z S, S, 20.57. a a

The infrared spectrum of this product was compatible with the above structure. 7

When the 3,4-diamino-Z,S-dicyanothiophthene of Example 4 or 3,4-diamino-2,S-dicarbethoxythiophthene of Example 5 is hydrolyzed, 3,4-diamino-2,S-dicarboxythiophthene as well as some 3,4-diamino-2-cyano-5-carboxythiophthene and 3,4-diamino-2-carbethoxy-5-carboxythiophthene, respectively, will be produced.

The products and processes of this invention have been illustrated by the specific Examples l-S. However, the invention is generic to the 3,6-diamino-2,5-disubstitutedthieno(3,2-b)thiophenes and the 3,4-diamino-2,5-disub stituted-thiophthenes of Formulas III and IV. Additional specific examples of 3,6-diamino-2,S-disubstituted-thieno- (3,2-b)thiophenes, the 1,2-dicyanoethylene bis(substituted-methyl sulfides) from which they can be formed by the process of this invention, and bases which bring about the reactions are listed in Table I.

Found:

3,4 -diamin0-2,5 -dicarbethoxythiophthene TABLE I 1,2-dicyanoethylene bis-(substituted-methyl sulfide) 3,6-dia1nino-2,fidisubstituted-thieno(3,2-b)thiophene RCHZS SCI-12R S Base (pKb) HzN -R NO ON R NH;

R R R R H NC o o o 0-@ Diisopropylamine 2.95 H N o o c 0 0Q 0330 O C 0 CH3 Ammonia (4.74) CHKC O C 0 CH ii-C 11 O O C N 1-(-g5tyD-piperidine n- 0 H25 C O C N Benzyltrimethylammo- CH1S 02 S O CH: hydroxide (0a., OH SO; SO C H:

CH7(3H1 P Z 4 CHz-CH: CHrCHg C CHOCO COOCII /CH:4 Trimethy1amine(4.28) CH; OHOOO COOCH /CH GE -C Hg CHPCH: C Hr-C Hg CH2OH2 n-CsHnOCO CO0CH2CH=CH2 Beir izum hydroxide (0a., n-CaHnOCO CO0CH2CH=CH2 C N C N Potassium hydroxide (0a., 0 N C N (OHIOQNCO CON(CHa)z S01d7il)1m hydroxide (ca., (CH3):NCO CON(CH3)2 NH O O C N Tetraethylammonium NH O O C N hydroxide (021., 1.7).

CHaCECCO COOCH(CzE )g Tetraethylammonium CHaCECOO COOCH(C2H5)2 hydroxide (ea., 1.7).

(CzF )(CFs)CF SOzCHs Hydrazine (5.52) (CzF5)(CF3)CF SOzCHs EXAMPLE 5 Similarly, additional specific examples of 3,4-diamino- 2,S-disubstituted-thiophthenes, the 1,1-dicyanoethylene bis(substituted-methyl sulfides) from which they can be prepared, and bases which bring about the reactions are listed in Table II.

TABLE it i i i i 1,1-dicyanoethylene bis-(substituted-methyl sulfide) 3,t-diaminofi,5-disubstituted-thiophthene RCHQS. i T.-J -NH:

' C=C(ON); Base (pKs) e I 7 1 V n oms A oni=omonmoo onz=omonmoo V Ammonia (4.74);

Sodium hydroxideica 1.7)

. 10 minutes more to' insure complete reaction.

brought about precipitation of a solid, bright-yellow prod V -ouaoo o 7 No n-Pentylamine 3.3s) n-C5H7Q o 7 CN w, Fae Pymfliaine 2 .89) @ao: F3 (oHmoHoo 0 No Strontium hydroxide (ca, 1.7 (011920130 0 o CN n-oimo'o o v n-oirrio c 0 Cyclohexylaminc (3.36) n-cinno o o V o 0 0n-oiH9- Nno 0 V 0530 0 0 Triethylamine (3.25) NHO o o o 0 OH;

N02 OgN V 2-phenylethylamine (4.17) N02 7N0;

HzNC O C2H5O C. Tri-n propylamine (3.30) HQNC 0 7C O C2H5 'oziitooo OHC 7 l-methylpyrollidine (3L's2 0211.000 7 0nd g l V 11-Cr2Hz5NH C O D'CLZHENH O 0 Potassium hydroxide (ca. 1.7)- n-C12H25NH C O C O NH-fll-CmHzs CH2=C=CHCH2OH2OO n-G HUOCO Ammonium hydroxide (021., 1.7), CH2=C=CHCE2CH2OO HC5H11O O0 n-O F OzN Q- henylethy'lamine (4.17) 11 081331 OzN NC 7 D-CizHgsO o 0 Sodium hydroxide (ca.. 1.7 o 0 o 0-1-0355 The products of this invention are useful as intermedi A ates in the preparation of dyes for textiles.

For example, 3,4-diamino-2,S-diCanbethoxythiophthene (Example 5) can be reactedwith benzaldehyde Io. give a brightyellow dye. A mixture of 3 parts of the thiophene derivative and parts of benz-aldehyde was boiled. until solution was complete (about 10 minutes), and then for uct. 'I wo parts of the product were. dissolved in IOparts Cooling nin (M'ar'asperseCB) in 2,000 parts of water. Swatches of polyamide, polyacrylonitrile, polyester, silk, wool,-and cellulose acetate fabrics were immersed in this dye bath, andthe bath was heated on a steam bath for one hour.

After removal, washing with mild soap, and dryin the swatches were dyed light yellow, the exact shade depending on the dye and the fabric.

In addition to their use as intermediates to dyes, some of the products of this invention are dyes themselves. For example, 3,6 diamino 2,5 dibenzoylthieno(3,2 b)- thiophene (Example 1) was used to dye the fabrics mentioned above various shades of'yellow by the methodjust' described.

Since obvious modifications and equivalents int-he in:

vention will be evident to those. skilled in the chemical.

wherein each of A and A'is selected from the group con-' sisting of ON, NO perfiuoro alkyl of up to 12 carbons, CHO, -COR", SO R, -COOR", CONH hydrocarbyl of up to 12 carbons, and Q and Q being hydrocarbyl. together totalling up tolZcaIbons 1 2. 3,6-diamino-2,5-dibenzoylthieno( 3,2-b) thiophene. 3. 3,4diamino-2,5-dibenzoylthiophthene, r 4. 3,4-diamino-2,S-dicyanothiophthene. i

5. The process of preparing3,6-diamino-2,5-disubstitutedthieno(3,2-b)thiophenes and 3,4-d-iamino-2,5-disu b.

stituted thiophthenes which comprises selfeconden'sing a dicyano compound of'a formula selected fromthe group consisting of:

' wherein each of R and R is selected from the group con- 7' sisting'of CN,1'-NO perfluoroalkyl of 'up to 12 cara II o and ROHzS bons, CHO, COR", SO R", COOR", CONH -CONH(R) and CON(Q) to R" being hydrocarbyl of up, to 12 carbons, and Q kandQ being hydrocarbyl 6. The-process of claim 5 wherein said molar ratio is in the range of 0. 5:1.0 to 4.0: 1 .0.. i

7. The process of claim Swherein the self-condensation is carried out in the presence of an inert solvent for said dicyano compound and said base. V

8. The process of claim 5 wherein said dicyano compound is 1,2-dicyanoethylene bisfibenzoylmethyl sulfide).

9. The process of claim 5 wherein said dicyano compound -is 1,1-dicyan0ethylene bis ('benzoylmethyl sulfide).

10. The process of claim 5 wherein said dicya-no compound is 1,1-dicyanoethylene bis(cyanomethyl sulfide).

11. The process of claim 5 wherein said dicyano compound is l,l-dicyan-oethylene ibis(carbethoxymethyl sulfide).

12. 3,4-diamin0-2,S-dicarbethoxythiophthem,

10 References Cited by the Examiner Degering: An Outline of Organic Chemistry, Barnes and Noble Inc., New York (1951), pages 135-6.

Gornpper et al.: Angew. Chernie (Internat. Ed), vol. 1 (1962), page 216.

'Hartough et al.: Condensed Thiophenes, Intel-science Publishers, Inc., New York, N.Y., 1954, pp. 372-381.

IRVING MARCUS, Primary Examiner.

1G WALTER A. MODANCE, Examiner. 

1. A COMPOUND OF A FORMULA SELECTED FROM THE GROUP CONSISTING OF: 